In just three hours after the earthquake hit the Sumatra Islands on December 26, 2004, Kalpakkam-based Madras Atomic Power Station (MAPS) experienced its first tsunami.
Though Unit-2 was operating at near full power on that day, it was safely shut down due to the presence of inbuilt safety systems.
Following the Fukushima event in Japan, safety measures across all nuclear power stations in the country have gone up. Now, apart from the emergency diesel generators and firefighting pumps, they are fitted with additional hookup points to pump water to boilers.
Subsequent to tsunami, improvements such as tsunami bund of boulders as part of Prototype Fast Breeder Reactor (PFBR) outfall channel has been added in MAPS. This will absorb considerable energy from the ocean waves and result in lesser wave height when it reaches the shore.
Apart from seismically re-evaluating all MAPS units, all emergency power equipment, de-aerator storage tank and piping have been strengthened from severe earthquake consideration viewpoint.
An earthquake notification system, installed in MAPS control room, constantly scans seismic sites in Europe and the US.
In case of any earthquake that is more than 7.0 on Richter scale with the epicenter in the sea at the depth of less than 15 km in the Asia Pacific region, it reviews with official centres in the country to activate tsunami-warning system. Mitigating actions for safe shutdown of site reactors are then taken within anticipated time of about 2-3 hours.
Also, as per Atomic Energy Regulatory Board stipulations, all key operating personnel of the plant are licensed only after rigorous training and qualifying tests. This ensures that reactor operators are competent to handle off-normal situations in the plant.
All Indian nuclear power plants have inherent design strengths to deal with natural events. The efficiency of these design features were amply demonstrated during long station blackout caused by a turbine hall fire incident at Narora Unit 1 (UP) in 1993, and also during the flooding event at Kakrapara Atomic power plant (Gujarat).
All nuclear power plants undergo periodic safety review to implement system upgrades thereby enhancing their safety. The safety record of our nuclear power plants has been consistently excellent with over 350 reactor years of operation.
In India, submarine faults capable of generating large tsunamis are located at very large distances of more than 800 km from western coast and 1300 km on the eastern coast.
Thus unlike in Fukushima, simultaneous occurrence of a strong earthquake and a tsunami at our plants is not foreseen.
(The author is the Station Director of MAPS.)
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